#pragma warning(disable:4996)
#include<stdio.h>
#include<math.h>
int main()
{
    double diameter1, diameter2, r1, r2, v1, v2, v, length;
    scanf("%lf %lf", &diameter1, &diameter2);
    r1 = diameter1 / 2;
    r2 = diameter2 / 2;
    v1 = 3.1415926 * pow(r1, 3) * 4 / 3;
    v2 = 3.1415926 * pow(r2, 3) * 4 / 3;
    v = v1 + v2;
    length = cbrt(v);
    printf("length of the side is:%.2lf.", length);
    return 0;
}